Technical Abstract:
Thelytokous parasitoid strains are theoretically advantageous when utilized for biological control, as the absence of males should reduce production costs and potentially increase field efficacy. The maternally inherited intracellular bacterium, Wolbachia pipientis, is capable of inducing reproductive alterations in parasitoids and other arthropods, including parthenogenesis induction, or thelytokous reproduction without males. We utilized indistinguishable sympatric arrhenotokous and thelytokous Odontosema anastrephae Borgmeier (Hymenoptera: Figitidae) fruit fly parasitoid strains to test the relative utility of each reproductive type for mass rearing and biological control. Multi locus sequence typing and antibiotic curing demonstrated that thelytokous O. anastrephae are singly infected with a novel Wolbachia strain likely responsible for parthenogenesis induction. Although uninfected arrhenotokous (W-) O. anastrephae display protandry, average female development time was not different between strains. Estimates of population doubling time were shorter for thelytokous Wolbachia-infected (W+) females when both strains were individually maintained, yet the reverse occurred when strains were reared in groups. This was primarily due to the significantly shorter lifespan of group-maintained W+ females, and despite W- females producing an increased proportion of male offspring when competing for hosts. For logistical reasons, mass-rearing schemes require parasitoids to be reared in groups. Therefore, we believe it is unlikely that Wolbachia-infected thelytokous O. anastrephae would be advantageous relative to uninfected arrhenotokous strains for augmentative release programs.